As LSI circuits are increasing in density, the required linewidths of circuits included in semiconductor devices become finer year by year. To form a desired circuit pattern on a semiconductor device, a method is employed in which a high-precision original pattern (i.e., a mask, or also particularly called reticle, which is used in a stepper or a scanner) formed on quartz is transferred to a wafer in a reduced manner by using a reduced-projection exposure apparatus. The high-precision original pattern is written by using an electron-beam writing apparatus, in which a so-called electron-beam lithography technique is employed.
A drawing apparatus using a multi-beam can irradiate with many beams at once, as compared with the case where drawing is performed by a single electron beam, thus the throughput can be significantly improved. In a multi beam drawing apparatus that uses a blanking aperture array, which is one form of multi beam drawing apparatus, for instance, electron beams emitted from an electron gun are passed through a shaping aperture array having multiple openings, and a multi-beam (multiple electron beams) is formed. The multi-beam each passes through a corresponding one of blankers of the blanking aperture array.
The blanking aperture array includes an electrode pair for deflecting a beam individually, and an opening for beam passage between the electrode pair, and one of the electrode pair (blanker) is fixed to the ground potential, and blanking deflection is performed individually on a passing electron beam by switching the other electrode between the ground potential and a potential other than the ground potential. An electron beam deflected by a blanker is shut off, and a sample (a mask) is irradiated with an electron beam not deflected.
As the shaping aperture array is irradiated with a beam, the temperature of the shaping aperture array increases, and an opening pitch is changed due to thermal expansion. When the opening pitch of the shaping aperture array is changed, a problem arises in that the beam pitch of the multi-beam is changed, and some beams cannot pass through the openings of the blanking aperture array, thus part of a beam array, which is to form an image on a sample surface, is lost.